C.diff. non-epidemic Spores
The left plate above is the control (no Sterilray treatment)
The right plate is 5 secs of Sterilray on high power ~100mj/cm2.
The control has ~5-6 logs of spores and the right plate ~2 logs after treatment.
The spores are non-epidemic, 99.9% clean, bright phase (dormant, not germinated) spores in water.
A 4″x4″ square area of the labtop was inoculated and the spore suspension was allowed to dry.
The area was touched with sterile gloves and then touched directly to pre-reduced C.diff agar plates and placed in the anaerobic chamber to incubate for 48 hours.

Briefly, epitheial cells were exposed to UV from Far-UV Sterilray™ at lowest power setting for 5 and 10-minute durations.

n= 2 for each treatment group but it does not include variance because the differences in the means between treatments were so large.

Interpretation of the data: Clearly cells not protected by epidermis are drastically affected by Far-UV Sterilrayat 5 and 10 minutes.

The endpoint MTT assay indicates that the apparent cell number has dropped 70% from controls.

Placing human epidermis into the lightpath appears to confer protection to the cells because, within the constraints of the experimental design, the Far-UV dose was insufficient to compromise cell viability.

The caveat here is that MTT is an endpoint assay so will not reveal sub-lethal cell stress per se, especially relevant is genotoxic effects, comet, and kinetic XTT or WST1 are required for that as a minimum but is certainly feasible.

On the basis of the results from this look-see experiment, it appears that Far-UV Sterilray™ does not penetrate human epidermis at sufficient doses to compromise cell viability as measured by MTT assay.

This experimental approach and the related data on its own is nowhere near rigorous enough to support a claim that Far-UV Sterilray™ exposure of human skin is ‘safe’.

C.diff. non-epidemic Spores
The left plate above is the control (no Sterilray treatment)
The right plate is 5 secs of Sterilray on high power ~100mj/cm2.
The control has ~5-6 logs of spores and the right plate ~2 logs after treatment.
The spores are non-epidemic, 99.9% clean, bright phase (dormant, not germinated) spores in water.
A 4″x4″ square area of the labtop was inoculated and the spore suspension was allowed to dry.
The area was touched with sterile gloves and then touched directly to pre-reduced C.diff agar plates and placed in the anaerobic chamber to incubate for 48 hours.

Briefly, epitheial cells were exposed to UV from Far-UV Sterilray™ at lowest power setting for 5 and 10-minute durations.

n= 2 for each treatment group but it does not include variance because the differences in the means between treatments were so large.

Interpretation of the data: Clearly cells not protected by epidermis are drastically affected by Far-UV Sterilrayat 5 and 10 minutes.

The endpoint MTT assay indicates that the apparent cell number has dropped 70% from controls.

Placing human epidermis into the lightpath appears to confer protection to the cells because, within the constraints of the experimental design, the Far-UV dose was insufficient to compromise cell viability.

The caveat here is that MTT is an endpoint assay so will not reveal sub-lethal cell stress per se, especially relevant is genotoxic effects, comet, and kinetic XTT or WST1 are required for that as a minimum but is certainly feasible.

On the basis of the results from this look-see experiment, it appears that Far-UV Sterilray™ does not penetrate human epidermis at sufficient doses to compromise cell viability as measured by MTT assay.

This experimental approach and the related data on its own is nowhere near rigorous enough to support a claim that Far-UV Sterilray™ exposure of human skin is ‘safe’.